As a welding gun equipped to a robot or the like, conventionally, the guide type of welding gun has been known that is configured so as to include a fixed gun arm fixed to a gun body, a mobile gun arm opposing the fixed gun arm, and a drive device equipped to the gun body side; connect the mobile gun arm to an arm holder that is movable along a guide groove formed in the gun body side; and cause the mobile gun arm to undergo an opening/closing operation via the arm holder by way of the drive device.
In such a welding gun, a work is sandwiched between the electrode tips at the leading ends of the fixed gun arm and mobile gun arm by closing the mobile gun arm, and there is a risk of welding slag flying from the spot point on the work then passing through a gap between both gun arms and penetrating into the gun body. In other words, the internal mechanisms of the gun body are fouled by welding slag, which becomes one of the main causes of the durability of the gun body declining.
For this reason, to date, a gun has been disclosed in Patent Document 1 that provides a sheet-like cover member, fixing one end of the cover member to a portion of the gun body positioned in a gap between the fixed gun arm and mobile gun arm in a closed state of the mobile gun arm, and fixing the other end of the cover member to an arm holder. According to this, the cover member is unfolded and folded accompanying the opening/closing operation of the mobile gun arm, and the incursion path of welding slag to the gun body is always shielded irrespective of the opening/closing of the mobile gun arm by the cover member.    Patent Document 1: Japanese Unexamined Patent Application, Publication No. H11-245051